An iceberg at Marguerite Bay on the Antarctic Peninsula. New research finds that 24% of West Antarctic ice is now unstable. (Photo: Andrew Shepherd)

The ice has thinned by some 400 feet in some places, the study said. The ice sheet and its glaciers are melting from underneath as warming sea water – overheated due to man-made climate change – chews away at it from below.

This map shows changes to the Antarctic ice sheet’s thickness from 1992 to 2017. Ice loss is in red while ice gained is in blue. (Photo: Shepherd et al 2019/Geophysical Research Letters/AGU.)

“Along an 1,850-mile stretch of West Antarctica, the water in front of the glaciers is too hot,” Shepherd told the Guardian. “This causes melting of the underside of the glaciers where they grind against the seabed. The melting lessens the friction and allows the glaciers then to slide more quickly into the ocean and therefore become thinner.”

A reminder: This isn’t the floating sea ice around Antarctica, which melts and refreezes with the seasons. This is freshwater ice on the gigantic ice sheets and in the glaciers that cover most of the continent.

The ice is unstable because melting and calving (the breaking off of ice chunks) is reducing their mass faster than it can be replenished by snowfall, CNN reported.

The melting contributes to rising sea levels around the world: “Altogether, ice losses from East and West Antarctica have contributed 4.6 millimeters (about 1/5 of an inch) to global sea level rise since 1992,” Shepherd said.

The study was published in the peer-reviewed journal Geophysical Research Letters, a publication of the American Geophysical Union.

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